Biology subjects

Schenk, A.

Publications and source records attributed to Schenk, A..

5 recordsLinked to original sources

bioRxiv2025

Predicting Antifouling Paint Particle Contamination based on 16S rRNA Gene Sequencing Data using Random Forest-Based Machine Learning

Antifouling paints often contain biocides designed to inhibit biological growth, and antifouling paint particles (APPs) have been previously shown to affect microbial communities in sediment. Given typical methods for monitoring for APP presence can be specialised and challenging, alternative methods using simple, standardised and universal approaches, such as 16S rRNA amplicon sequencing, would be highly valuable. This study uses a field-based mesocosm approach to train a random forest-based (supervised) machine learning model to predict APPs presence and concentration in sediment based on 16S microbial community data. The model correctly predicted 100% APP-presence samples and 83.3% APP-absence samples in the incubation testset, although the model could not correctly predict APP concentration with sufficient accuracy. To determine real-world applicability of the model, samples from 14 different sites along the Baltic Sea coastline and Warnow estuary in NE Germany were collected and APP-presence was pre-determined using SEM-EDX spectroscopy. The model correctly assigned APP-absence status to all APP-absent sites, and correctly assigned 3 of 5 APP-contaminated sites as having APP presence. As such, these results confirm it is possible to predict APPs in sediment based on the microbial community, and serves as a proof-of-concept for the further development of machine learning-based predictive tools for environmental monitoring.

microbiology↗

bioRxiv2025

Hepatocyte Circadian Clocks Control Cholesterol Metabolism and Protect From Metabolic Dysfunction-Associated Steatohepatitis (MASH)

The circadian clock synchronizes physiological processes with the 24-hour light-dark cycle. Clock disruption contributes to metabolic disorders, including metabolic dysfunction-associated steatohepatitis (MASH). Here, we investigated the role of the hepatocyte clock in MASH using hepatocyte-specific Bmal1 deletion (Hep-Bmal1KO) mice. Hep-Bmal1KO mice showed faster MASH progression with increased hepatic cholesterol, inflammation, and fibrosis. Transcriptomic and lipidomic analyses revealed dysregulated cholesterol metabolism in Hep-Bmal1KO mice, marked by reduced expression and disrupted rhythmicity of key cholesterol-related genes. Bioinformatic analyses identified Chrebp as a potential co-regulator of these transcriptional changes. In an in vitro model with palmitate exposure and gene silencing, we found that Bmal1, but not Chrebp, regulated cholesterol accumulation, indicating Bmal1s specific role in hepatic cholesterol metabolism. Translating our findings to a human patient cohort revealed a significantly shifted circadian phase, despite no marked effect on hepatic cholesterol levels in the livers of patients with more advanced liver disease (i.e., MASH) compared to simple steatosis. Taken altogether, our findings offer a roadmap to understand the hepatocyte clocks role in MASH and its potential as a therapeutic target.

pathology↗

bioRxiv2024

Pear (Pyrus communis L. cv. Conference) has shade-tolerant features allowing for consistent agrivoltaic crop yield

Transitioning to a fossil fuel free society requires an increase in solar energy production. However, expanding solar power to farmland competes with food production. Additionally, climate change threatens food security and leads increasingly to yield losses. Agrivoltaics (AV) systems produce solar energy and food on the same field, while sheltering crops. In AV systems, crops grow in a modified environment with reduced solar irradiance, a tempered microclimate and a potential physical cover protecting against hail damage. This research describes pear production under an AV pilot with 24% light reduction for 3 consecutive seasons. AV pear trees yielded 14% less than the reference. Flowering and fruit set was unchanged while AV reduced leaf flavonoid levels. The leaf photosynthetic light response was identical, yet a delayed leaf senescence under AV suggests an adaptation to the modified environment. AV impacted fruit shape, as there was an increase in the number of bottle shaped pears and a reduction in caliber. Other fruit quality traits were broadly unaffected, yet postharvest ethylene production was higher for AV fruit in 2022 than for the control. This study demonstrates that AV systems hold potential for pear production under temperate climates and highlights plant adaptations that make this possible. HighlightPear cultivation in agrivoltaic systems integrates renewable energy and sustainable fruit production. This study provides insights into crop yield, fruit quality, and plant adaptation towards an agrivoltaic environment.

plant biology↗

bioRxiv2024

Acute exercise increases systemic kynurenine pathway metabolites and activates the AHR in human PBMCs

The kynurenine pathway of tryptophan degradation generates several metabolites such as kynurenine or kynurenic acid that serve as endogenous ligands of the aryl hydrocarbon receptor (AHR). Due to its distinct biological roles particularly modulating the immune system, the AHR is a current therapeutic target across different inflammation-related diseases. Here, we show an exercise-induced increase in AHR ligand availability on a systemic level and a kynurenine pathway activation in peripheral mononuclear blood cells (PBMCs). Concurrently, the AHR is activated in PBMCs following acute exercise, with effects being dependent on exercise intensity. In conclusion, these data indicate a novel mechanistic link how exercise modulates the immune system through the kynurenine pathway-AHR axis, potentially underlying exercise-induced benefits in various chronic diseases.

immunology↗

bioRxiv2020

Influence of normobaric hypoxic exercise on endothelial progenitor cell senescence by in vitro cultivation with conditioned media

ObjectiveCirculating endothelial progenitor cells (EPCs) were shown to be affected in cardiovascular and metabolic diseases. As interventional strategies, hypoxia and exercise are both known to increase the number and enhance the function of EPCs, potentially by extending their lifespan induced by a reduced senescence. Therefore, this pilot study investigated the effect of exercise under normobaric hypoxia on the senescence of EPCs by in vitro cultivation with autologous human serum (AHS). MethodsFour healthy trained young males (23 {+/-} 2 years) performed an incremental cycling step test until exhaustion in a normobaric hypoxic-chamber with an average altitude of 4,000 m (O2 12.3%). Blood serum was taken at pre, 10 min post and 4 h post, which was later used for in vitro cultivation of EPCs. Senescence was investigated by {beta}-galactosidase staining. ResultsThe participants spent 30-40 min in normobaric hypoxia. The EPC senescence rate was reduced 10 min (0.72 {+/-} 0.57%) and 4 hours (0.67 {+/-} 0.52%) after exercise compared to pre (1.89 {+/-} 0.37%). ConclusionThis pilot study indicates that intense exercise under normobaric hypoxia may enhance EPC function by slowing down their senescence.

physiology↗